The present invention relates to a white ink composition for ink jet textile printing by which even if printing is carried out without discoloring the dye of textile piece, the whiteness degree of a dyed article obtained is high and the dyed article superior in coating film durability and laundering fastness is further obtained without losing the drape of the textile piece, and an ink jet textile printing process using the white ink composition for ink jet textile printing.
Handwriting and a screen printing system have been conventionally main in a printing process, but the utilization of an ink jet recording process capable of extremely simple and continuous dying for long textile piece has been recently carried out often.
Further, as the ink utilized, aqueous ink using a pigment as a coloring agent has been marked in place of a dye that is brilliant and broad in reproducible color area but to the contrary, low in light stability and troublesome in post steps such as fixation, rinsing with water and waste liquid treatment.
Concerning printing on textile piece with deep color, a process is mainly carried out, in which the dye of a printing portion is preliminarily removed by using a discharging agent and then aqueous ink using the above-mentioned pigment is printed.
The process has a problem that the color of the textile piece from which the dye of the textile piece was removed is assumed as white but since the whiteness degree is imperfect, the sharpness of an image in inferior when printing is carried out on the portion.
As a process for solving the problem, there has been recently carried out a process of directly printing on textile piece with dark color using white ink jet ink and further printing with colored ink jet ink.
As the white ink jet ink printed on the textile piece, there are proposed, for example, processes such as a process of printing a white ink composition for ink jet textile printing including hollow polymer particles as a white pigment (for example, refer to Japanese Unexamined Patent Publication No. 161583/2005) and a process of printing a white ink composition for ink jet textile printing including a pigment, an anionic aqueous resin and two kinds of a low melt flow resin emulsion with a melt flow temperature of 60 to 100° C. and a high glass transition temperature resin emulsion with a glass transition temperature of 140 to 200° C. (for example, refer to Japanese Unexamined Patent Publication No. 288636/1996).
However, there are problems that when the hollow polymer particles are used as the white pigment, adequate whiteness degree cannot be obtained and when an ink composition including a resin emulsion with a glass transition temperature of at least 140° C. is printed, the drape of the textile piece is damaged.